Z-Source Inverters for Advanced Power
Conditioning of Alternate Energy Systems
Abstract—Alternate energy sources such as solar, fuel cell, and wind have a wide voltage change range due to the nature of the
sources. Photovoltaic cell’s voltage varies with temperature and irradiation. Fuel cell stack voltage drops greatly with current.
And wind generator voltage varies with wind speed and control. The traditional voltage source inverter that has been the power
conversion technology for these energy sources cannot cope with this wide voltage change nature and often requires additional
voltage boost by additional dc/dc converter. The Z-source inverters can solve this problem. This single stage power conversion
technology provides a great alternative with lower cost, higher reliability, and higher efficiency. System configurations, features
and results are shown for advanced power conditioning of alternate energy systems.
Quasi-Z-Source Inverter for Power Conditioning of Photovoltaic Systems
Features:
Single power stage for buck and boost, power inversion, and maximum power point tracking;
Minimum number of switching devices;
More reliable and lower cost; High immunityUtilityto EMI noise and high efficiency.
C2
iL1
L1
D1
v2 (100 V/div)
i2 (50 A/div)
L2
iL2
VC1 (100 V/div)
Sa1
Sb1
Sc1
C1
Vpv
v1 (100 V/div)
ia
La
Lb
Lc
V pv (100 V/div)
Ca
Sa2
Sb2
Load
Sc2
i1 (50 A/div)
Z-Source Capacitor
Voltage & Input Voltage
Quasi Z-Source Inverter for
Grid Connected PV PCS
Output Voltage
& Load Current
10 kW Z-Source
Inverter Prototype
Quasi-Z-Source Inverter of Fuel Cell Battery Based Distributed Power Generation
Features:
One single inverter stage to interface FC and battery,
boost voltage, and perform energy management;
Production of desired ac voltage for a wide FC voltage
range (1:2);
Minimum numberBattery
of switching devices;
Utility
iL1
L1
D1
iL2
Constant current from FC and independent battery SOC
control;
High efficiency;
High reliability and low cost.
V0 (200 V/div)
VPN (200 V/div)
L2
IL1 (20 A/div)
Sa1
Sb1
Sc1
La
Lb
Lc
C1
ia
vLab (200 V/div)
Ca
Fuel Cell Stack
Sa2
Sb2
Load
Sc2
Quasi-Z-Source Inverter Configuration of FC-Battery PCS
Experimental Waveforms
showing voltage boost
55 kW Z-Source Inverter Prototype
Experimental Waveforms showing
Z-Source Inverter for Wind Power Generation Systems
that the Z-source inverter can
Features:
produce desired 230-V rms for a
wide range of generator voltage
Single active power stage to perform voltage boost and maximum power point tracking;
(115—230V
from
low
to
high
wind)
Production of desired output voltage and MPPT for a wide range of wind speed;
Minimum components count; Reliable,
low cast, and high efficiency.
L
1
Gen Voltage vGab
115V RMS
Gen Voltage
230V RMS
Gen Current iGa
Cin
C2
C1
Sa1
Sb1
Sc1
Li
Lin
Output Voltage vLab
after LC, 230V RMS
G
Output Current iLa
Inverter Current
Ci
Sa2
Sb2
Sc2
L2
Z-Source Inverter for Wind Power Generation System
At high speed wind
At low speed wind
Power Electronics and Motor Drives Laboratory
Contact Info: Fang Z. Peng, fzpeng@egr.msu.edu, 517-336-4687